Helter Skelter: The True Story of The Manson Murders is a 1974 book by Vincent Bugliosi and Curt Gentry. Bugliosi had served as the prosecutor in the 1970 trial of Charles Manson. From Wikipedia
Errol Morris' documentary adapts Tom O'Neill's book to explore alternative explanations and unanswered questions surrounding the 1969 Manson murders.
